Ash and Goh come across a large school of Tentacool off the coast of Vermilion City. Ash is particularly excited and pokes one, only to find out that Tentacool are soft and squishy. In response, the Tentacool lashes out at Ash with a Bubble Beam to the face. Goh decides to add a Tentacool to his collection of Pokémon. With a curve ball throw, he catches one, and the Pokédex immediately updates itself. The Tentacool suddenly float away as something swims towards the shore at a rapid pace.
A particularly lean Piplup leaps from the ocean, and collapses from exhaustion. The boys take it back to the Cerise Laboratory, where Piplup proceeds to gorge itself on food. Chloe soon returns home to find everyone staring at something. Goh explains that it is a Piplup, but Chloe looks down at her feet and only sees an empty food bowl. Mimey frantically enters the room, and orders everyone to the bathroom. There, they watch as Piplup swims laps in the trough. Ren orders everyone into the lab, where they receive a call from Piplup's Trainer, Lauren. She explains that Piplup swam off from Snowpoint City, a northern city in Sinnoh, without reason. Piplup, however, appears unhappy to see Lauren again. Professor Cerise replies that they will return Piplup, so Ash and Goh volunteer themselves for the task.
Later, Ash and Goh sail across to the frigid Snowpoint City. On board, Goh points out a poster for the upcoming Pokémon Iceberg Race competition. Unbeknownst to them, Team Rocket is trailing behind in their Magikarp submarine, hoping to kidnap Pikachu and all the competition Pokémon. James, however complains that all the peddling from Kanto to Sinnoh is exhausting, and Meowth replies they have no money in the budget for an all-electric upgrade.
Arriving at Snowpoint City’s port, Ash looks for Lauren. Goh, on the other hand, has spotted a new Pokémon to catch. He has Scorbunny kick an ice block into the ocean, startling a passing Mantyke, which Goh proceeds to catch with ease. The crowd claps for the successful catch, which is when Lauren notices Ash and her Piplup. Lauren apologizes for the delay, admitting that she dropped her glasses. She goes to pat Piplup, but it is still unhappy with her. Lauren officially introduces herself to the boys, but drops her glasses in the process. Piplup immediately picks them up, and Lauren is grateful for its help. She suggests they return home, but Piplup wriggles out of her grip, still mad about something. The arrival of Lauren’s rather affectionate Croagunk clarifies the matter, as Piplup and Croagunk immediately exchange glares. Goh realizes the two Pokémon are rivals, though Lauren still cannot understand Piplup's sudden disappearance. She explains that she met Piplup a year ago, after it returned her glasses to her. The two quickly became friends, and Lauren won last year’s Iceberg Race with Piplup. Lauren adds that she only encountered Croagunk a month ago, after she dropped her glasses into the ocean. Piplup and Croagunk became competitive for Lauren’s attention and developed a bitter rivalry, which led to Piplup’s disappearance. Goh suggests Piplup must have left to beat Croagunk at swimming. Lauren turns to Piplup to confirm this theory, and it returns with two Drift Race entry stickers – one for itself, and the other for Croagunk. Seeing this, Goh runs over to the registration office to enter with his newly caught Mantyke, and Ash chooses Pikachu.
Soon, the Iceberg Race competitors are all lined up at the starting mark, while their Trainers watch from aboard a ship. The Pokémon must make their way through an icy obstacle course and through a set of two flags first to win. Several Chinchou use their light-emitting antennae to mark the course, while an Octillery waves its flags for the race to begin. Last year's runner-up, Masaya's Empoleon takes the lead, with Lauren's Croagunk and Piplup right behind it. Pikachu, meanwhile, is quickly falling behind as he attempts to leap from ice chunk to ice chunk. Seeing Pikachu struggling, Mantyke swims back to help him, impressing Goh with its remarkable manners. Empoleon begins to slow down, allowing Piplup and Croagunk to take the lead at the turnaround point.
The race comes to an abrupt stop when Team Rocket arrive in their Magikarp sub. With a push of a button, the trio snares most of the competition Pokémon except for Lauren's pair, Ash's Pikachu and Goh's Mantyke. The commentator is surprised by the interruption, and notes that Piplup and Croagunk are continuing to race ahead. Ash has Pikachu use Iron Tail, which frees the other Pokémon from the net. Team Rocket is furious, and call to the skies for Pelipper to bring them the Rocket Prize Master machine. Shoving Meowth headfirst, his golden charm activates the machine. With a turn of the crank, Jessie and James receive a pair of Rocket-branded Poké Balls, and they call out Machamp and Beartic. They begin to attack the Pokémon with ice projectiles. Goh orders Mantyke use Agility to evade, and Pikachu lands a Thunderbolt on the evil trio. James retaliates by having Beartic use Thrash on the ship, which throws Lauren over the guardrails. She holds onto the bow with one hand, calling for help, and then her glasses slip into the ocean below. The ripple sound from the falling glasses finally gets Croagunk and Piplup's attentions, and the pair rebound from the finishing mark to help their Trainer. Piplup uses its beak to free an inflatable lifeboat, while Croagunk knocks it in time to save Lauren from the icy waters with a Poison Jab. Lauren thanks her Pokémon for the rescue and retrieving her glasses, so she rewards them with a big embrace. Goh returns his attention to Beartic, and has Scorbunny deliver a Double Kick on it. Pikachu follows up with a mighty Thunderbolt, sending Team Rocket and their Prize Master Pokémon blasting off. Afterwards, the commentator announces that the race is immediately cancelled because of Team Rocket's interference.
No one seems to mind, especially not Lauren who is glad to see Piplup and Croagunk are finally getting along. However, after Goh and Ash ship off back to Kanto, Lauren encounters a new friend, this time a Psyduck after dropping her glasses again. Croagunk and Piplup are immediately shattered by the attention Psyduck receives.